Does the universe's recognition of measurement provide stronger evidence for being in a simulation than universal fine-tuning?
post by amelia (314159) · 2025-04-09T08:20:10.561Z · LW · GW · 0 commentsContents
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THE SIMULATION HYPOTHESIS
In 2003, Nick Bostrom used a probabilistic argument to introduce what became known as the simulation hypothesis: either advanced civilizations rarely emerge, they rarely run simulations, or we’re almost certainly in a simulation.(1)
FINE-TUNING AS SIMULATION EVIDENCE
Since then, public discourse has suggested the universe’s fine-tuning—the precise constants and conditions enabling life—supports the idea of being in a simulation. If there’s a “one in billions” chance of such fine-tuning occurring at random, then fine-tuning may hint at the existence of a fine-tuner, such as a programmer/simulator.
POSSIBLE DISMISSAL OF FINE-TUNING AS SIMULATION EVIDENCE
Most philosophers and cosmologists rely on multiverse hypotheses to argue against the idea that fine-tuning implies a fine-tuner. If billions of universes exist or have existed, our life-conducive outlier is possible, and nobody would be alive in universes that are not life-conducive to notice those cases. Thus, noticing that one is in a life-conducive universe no longer seems remarkable.(2) It is true that some individuals, such as Ian Hacking and Roger White, counter the counterarguments by arguing that multiverse hypotheses engage in logical fallacies—such as the Inverse Gambler’s Fallacy.(3) Yet most academics continue to dismiss fine-tuning with multiverse hypotheses. So is there any other physical evidence even mildly supportive of the hypothesis that we may be in a simulation?
THE DOUBLE-SLIT EXPERIMENT
During the double-slit experiment of quantum physics, photons and electrons exhibit wave-like interference when unmeasured, but act as particles when their paths are measured. More specifically, a particle begins in a superposition of two Gaussian wavepackets exiting two slits. Without measurement, these wavepackets spread and overlap, producing an interference pattern on a detection screen. However, introducing a measurement apparatus to determine which slit the particle passes through disrupts this pattern.
In the article "Measurement-induced Decoherence and Information in Double-Slit Interference" the authors explore how measurement precision affects this outcome, using a tunable apparatus which presumably interacts with the particle.(4) When the apparatus perfectly distinguishes the particle’s path, it entangles with the system, decohering the superposition into a state in which interference disappears. As precision decreases, partial interference reemerges, reflecting less information transfer to, or association with, the apparatus. When precision reaches zero (no measurement), no path information is gained, and we observe the interference pattern.
The authors suggest that measurement-induced decoherence drives the quantum-to-classical transition. When the apparatus or environment gains "which-path" information, it entangles with the particle, collapsing the superposition (as there is no longer a need for superposition) and erasing interference. The authors further suggest this reflects a broader principle: information acquisition by an observer or apparatus alters the quantum state.
This aligns with ideas like quantum Darwinism, in which classical reality emerges from redundant information storage, making interference observable only when path information remains inaccessible.
WHY DOES THE UNIVERSE RECOGNIZE MEASUREMENT “IN THE FIRST PLACE" DURING THE DOUBLE-SLIT EXPERIMENT, AND DOES MEASUREMENT-RECOGNITION SUPPORT BEING IN A SIMULATION?
While the above interpretation of the double-slit experiment reflects one interpretation of how we see what we see, it now becomes necessary to ask why the universe recognizes measurement, entangles measurers to particles, and engages in decoherence "in the first place"? It seems there is no clear advantage for the universe to do this. In fact, it seems it would be quite elaborate and excessive for the universe to keep track of all actions of all life and devices simply so that, if photon or electron path measurement should happen to occur, the universe can then collapse the superposition of said photon or electron. Continuous monitoring for measurement would seem to be exceedingly compute-intensive; that is, it would involve an enormous amount of information processing. By way of comparison, a simulated world made to resemble a universe would already need to be keeping track of actions like measurement in order to maintain the simulation. In this way, adding a "bonus" reaction to our measurements would require negligible additional processing, and might even be seen as something of a "wink" by a potential simulator. One could argue the program would save some infinitesimally-small amount of compute in terms of “rendering” by collapsing a superposition, but this negligible advantage could never outweigh the upfront cost of constantly monitoring for and recognizing measurement. The only way it would make sense to react to measurement would be if the “universe”/program is already tracking our actions, including measurement, in the first place.
Another sign of quantum entanglement support for the idea we are in a simulation comes from the fact that a programmer/simulator/intelligence would already know what it means to measure/observe/know and to “make something known” to an "environment." (A knower knows what it means to know.) Yet the possibility that a universe would simply evolve at random to be able to recognize and react to measurement, without any clear advantage for doing so, is hard to support. While humans have evolved to “know what it means to know” simply through natural selection of random mutations, we have done so on account of the tremendous competitive advantage of becoming intelligent. Yet there is no reasonably-conceivable advantage to a universe doing so, unless we were to speculate wildly, and imagine intelligent universes in competition with one another, with the most intelligent universe "winning." Even then, simulation programs could compete in this same way. There would be no advantage for "actual" universes to do this.
CAN WE DISMISS MEASUREMENT-RECOGNITION EVIDENCE WITH MULTIVERSE HYPOTHESES?
We were able to possibly dismiss fine-tuning as simulation evidence with multiverse hypotheses, given that such scenarios would make our observation of this universe's fine-tuning a mere selection effect. Is it similarly possible to dismiss our universe’s recognition of measurement as a selection effect in a multiverse? To answer this question, we have to think about whether we could still live in a universe that does not recognize measurement. During the double-slit experiment, if measurement were not recognized, there would be no quantum entanglement and decoherence, and we would be subjected to existing in a universe in which we could only see interference patterns. However miserable and unmysterious that might be, we would nevertheless survive. Therefore, we cannot dismiss the significance of measurement-recognition the way we dismissed fine-tuning.
CONCLUSION
So is universal recognition of measurement firm physical evidence that we are in a simulation? Perhaps not. However, it cannot be dismissed as easily as fine-tuning. If it may tip the scales ever-so-slightly, wouldn't that be something worth knowing? And finally, perhaps we should ask ourselves the following question:
If there really might be a simulator, or a "knower of what we (or our machines) measure/observe/know," would the knower know that we know?
CITATIONS
1-Nick Bostrom, “Are You Living in a Computer Simulation?,” Philosophical Quarterly 53, no. 211 (2003): 243–255.
2-Anthony Aguirre and Max Tegmark, "Multiple Universes, Cosmic Coincidences, and Other Dark Matters," Journal of Cosmology and Astroparticle Physics 2005, no. 04 (April 2005): 001, doi:10.1088/1475-7516/2005/04/001.
3-Roger White, "Fine-Tuning and Multiple Universes," British Journal for the Philosophy of Science 51, no. 2 (June 2000): 246–257.
4-Joshua Kincaid, Kyle McLelland, and Michael Zwolak, "Measurement-induced Decoherence and Information in Double-Slit Interference" (unpublished manuscript, n.d.), Department of Physics, Oregon State University, Corvallis, OR, and Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD.
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